Magnetic core matrices



April 20, 1965 E. HEIMBACH 3,179,927

MAGNETIC CORE MATRICES Filed July 2G. 1960 2 Sl'neets-SheerI 1 /n Venr EDGAR HE/MBACH April 2o, 1965 Filed July 20, 1960 E. HEIMBACH 3,179,927

MAGNETIC CORE MATRICES 2 Sheets-Sheet 2 /n Ven for EDG/ll? HE/MBACH Affe/WQ@ United States Patent Oiiice 3,l79,927. Patented Apr. 20, 1965 3,179,927 MAGNETIC CGRE MATRICES Edgar Heimhach, Munich, Germany, assigner to Siemens @e Halske Aktiengesellschaft, Berlin, `Germany, a German company Filed July 2t), i960, Ser. No. 44,169 Claims priority, applieatitsnlglsermauy, .luly 27, 1959,

9 Claims. (Cl. 340-174) This invention relates to magnetic core storage and/ or switching matrices having a plurality of magnetic cores threaded by a plurality of electrical conductors which are normally subject to the effects of considerable self-inductance.

As will be realised, each of the conductors threading the cores of such matrices has some self-inductance and this causes a back lil/LF. to be set up in opposition to driving pulse currents in the conductor. rlhis delays the rise and fall of the current pulse so that it is effectively lengthened and distorted. Thus an appreciable limitation is imposed upon the operating speed of the matrix, all pulses being subject to this distortion whether they are input pulses to or output pulses from the matrices. If the matrix is a large magnetic store using magnetic cores having approximately rectangular hysteresis loops, the pulses may be delayed and lengthened to such an extent that the storage cycle ofthe store has to be increased.

Accordingly, therefore, it is an object of this invention to provide magnetic core matrices in Which inductive effects in the conductors are reduced or substantially eliminated so that pulse distortion is minimal and the speed of matrix operation may be increased.

The present invention therefore generally includes a magnetic core matrix comprising an array of annular magnetic cores, a plurality of electrical conductors each extending between and threaded through a plurality of said cores, and a plate of non-magnetic electrically conductive material positioned adjacent said cores and said conductors to substantially reduce the self-inductance of said conductors.

rThe self-inductance of a conductor is dependent on the length of the path through air which has to be travelled by the magnetic flux set up by a current passing along the conductor. The shorter the air path, the lower the self-inductance.

One embodiment of the invention will now be described, by Way of example, with reference to the accompanying drawings, in which:

FIGURE l is a perspective view of part of a magnetic core storage matrix according to the invention;

FIGURE 2 is a perspective view of part of the matrix shown in FGURE l; and

FlGURE 3 is a perspective view showing a modification of the embodiment shown in FIGURE l.

Referring to FlGURE l, it will be seen that this is a perspective view of one layer of a three dimensional matrix. The layer consists of a plurality or magnetic cores M, control wires X each connecting together as dilerent row of cores and control wires Y each connecting together a different column of cores las can be seen. Output wires L are also provided, each connecting several cores together. The magnetic cores are located above a plate Pl of diamagnetic conductive material which has a plurality of projections Kl. Above the cores is shown another plate P2 of diamagnetic conductive material. This is shown in a raised position in order to show the cores M and projections Kl, but normally the plate P2 rests on an insulating frame R which acts as a support for the control wires and the output wires.

In addition to causing the effective inductance of the wires to be reduced, the plates P1 and P2 and the projections Kl cause a distributed capacitance to be established between them and the wires. This results in a further compensation of any self-inductance which remains. It will be appreciated that each conductor forms a wave conductor with the associated plates P1 and P2 and projections ll. Pulse currents passing along the conductors set up baclt E.M.F.s in the conductors and these are particularly disadvantageous when the store is associated with transistor circuits. The eiect may be obviated or substantially reduced by providing each wire at each of its ends with a reilectionless terminating impedance equal to the wave impedance of the corresponding wave conductor as shown in FIGURE l. Alternatively an impedance may be provided at only one end.

The wave impedance of the wires may be adjusted to a desired value by adjusting the distance of the conductive plate PZ from the magnetic cores M.

ln FIGURE 2 the same reference number is used for a part as is used for the corresponding part in FlGURE l. The frame R of insulating material which supports the control wires and the output wires has been removed for clarity as well as the conductor plate P2. lt will be seen from FIGURE 2 that the magnetic cores M rest on the conductive plate Pl, and this has projections Kl which are also conductive. ln this arrangement conductive bodies Kl are located adjacent to the outside cylindrical surface of each magnetic ring core, as also are the conductive plates Pl and P2. However a conductive body is not provided betweenkthe facing surfaces of adjacent magnetic ring cores in any row or column.

FEGURE 3 shows a further conductive body KZ located between the facing surfaces of a pair of cores in Va column. The body is also between a pair of cores in a row but the nearest core has not been drawn so as to show more clearly the position of the body K2. The body K2 ensures a further reduction of the self-inductance of the wires X, Y and L and is integral with the plate P1. It will be appreciated that a similar further conductive body may also be provided on the conductive plate P2. The bodies K2 must, of course, be limited in thickness so that there is still room for the conductor wires X, Y and L to be inserted.

it will be appreciated that the embodiment shown in FIGURES l to 3 may be modified. For example the empty space between the magnetic cores and the conductors may be tilled by casting metal therein. Care must, however, be taken that a conductive connection is not formed from a conductive body Pl or Kl, through the interior space of a magnetic core and back to the conductive body, thus short-circuiting that magnetic core. Such a short circuit winding on the magnetic ring core would prevent `an output pulse being obtained from the core on an output winding L when the polarity of the magnetisation of the core was reversed.

When pulse currents ow along wires the magnetic fields established normally penetrate only a short distance into any conductive body in the vicinity. Therefore the conductive bodies provided adjacent to the wires may each comprise a surface layer of conductive material on a non-conductive member. The conductive material of the plates and projections is conveniently copper.

The present invention is not exclusively limited to magnetic core storage apparatus employing cores having rectangular hysteresis loops. By the provision of a conductive body in accordance with the present invention it is possible to reduce the disadvantageous eiect of selfinductance in other apparatus also. However the invention is particularly suitable for application to magnetic core storage apparatus or magnetic core switching apparatus in which the inductance of the conductors is comparatively high dueto the large number of cores normally used and to the material of the magnetic cores.

What I claim as my invention and desire to secure by Letters Patent ofthe United States is:

1. A magnetic core matrix comprising: a plurality of annular magnetic cores` arranged in spaced arrays; a plurality of conductors each threaded through and extending between a plurality of said cores; a plate of diamagnetic and electrically conductive material arranged closely adjacent to and substantially co-extensive with said spaced array of said magnetic cores, said plate thereby having the effect of a` distributed capacitance upon each of said conductors whereby each of said conductors and said plate can be regarded as transmission lines with distributed components; and an impedance element connected from one end of eachv of said conductors tosaid plate, each of said impedance elements being equal to the characteristic impedance of the transmission line formed by the respective conductor and saidplate.

2. A magnetic core matrix substantially as claimed in in claim l wherein projections are formed on one side of said plate and extend into interstitial spaces between the cores of said array so as to locate said cores and to lie in close proximity to the portions of the conductors which extend between said cores, and wherein said projections and said plate are formed integrally by casting diamagnetic, highly-conductive material over said array.

3. A magnetic core matrix comprising: a first plate of diamagnetic, highly conductive material; a plurality of annular magnetic cores arranged in spaced array on said` irst plate so that the plane of each core is substantially perpendicular to the plane of the plate; a plurality of conductors` each threaded through and extending between a plurality of said cores; a second plate of said material arranged in substantially parallel and opposed relation to the first plate so that said cores are yarranged between said plates; and a plurality of projections upstanding fromV the surface of each plate adjacent said cores to laterally locate said cores therebetween, each of said projections extending between two adjacent cores in said array to lie closely adjacent the portion of each conductor which extends between said cores, and each of said projections being formed of said diamagnetic conductive material; said plates and said projections thereby co-operating to reduce the self-inductance of each of said conductors.

4. A magnetic core matrix comprising a plurality of annular magnetic cores arranged in spaced array, each core having two distinct remanent states; a plurality of conductors each threaded through and extending between a plurality of said cores; at least one plate of diamagnetic conductive material arranged adjacent to and substantially coextensive with said spaced array of said magnetic cores; a

plurality of projections of diamagnetic highly conductive material formed on the surface of said plate and arranged to extend into the interstitial spaces between the cores of said array to thereby locate said cores and lie in close proximity with the portions of the conductors which extend between said cores, said projections being formed integrally with said plate, and each conductor thereby forming a two-wire distributed-component Vtransmission line with said plate; and comprising a terminating resistor connected between one end of each conductor and said plate, said resistor having a value substantially equal to the characteristic impedance of the transmission line which that conductor forms with said plate.

5. A magnetic core matrix comprising a first plate of diamagnetic, highly conductive material; a plurality of annular magnetic cores arranged in spaced array on a surface of said lirst plate so that the plane of each core is substantially perpendicular to the plane of the plate; a plurality of conductors each threaded through and extending between a plurality of said cores, each one of said cores being let into and located by a recess formed in said surfacel of the first plate so that said conductors lie in close proximity to said surface; a second plate ofv said material arranged in substantially parallel and opposed relation to said lirst plate so that the cores are arranged between saidY plates; an annular frame member of insulating material encircling said array and arranged between said plates through which member each end of each conductor passes and by which each conductor is located; a resistor connected between one end of each conductor and said first plate and having a value substantially equal to the characteristic impedance of the associated conductor when that conductor and said plates areconsidered to form a distributed-component transmission line.

References Cited-by the Examiner UNITED STATES PATENTS 1,651,658 12/27 Young 336-87 X 2,307,447 1/ 43 Braaten 323-50 2,488,370 11/49 Boelens etal 323-50 X 2,581,202 1/52 Post 336-110 X 2,602,856 7/52V Rumsey 333-84 2,628,342 2/53 Taylor 336-73 X 2,712,126 6/55 Rosenberg et al. 340-166 2,751,558 6/56 Grieg et al. 333-84 2,823,372 2/58 Jones 340-174 2,900,624 8/59 Stuart-Williams et al. ,340-174 2,915,717 12/59 La Rosa 333-84 2,926,317 2/ 60 Blitz 333-84 2,945,216 7/60 Gyger et al 340-174 lRVING L. SRAGOW, Primary Examiner. 

1. A MAGNETIC CORE MATRIX COMPRISING: A PLURALITY OF ANNULAR MAGNETIC CORES ARRANGED IN SPACED ARRAYS; A PLURALITY OF CONDUCTORS EACH THREADED THROUGH AND EXTENDING BETWEEN A PLURALITY OF SAID CORES; A PLATE OF DIAMAGNETIC AND ELECTRICALLY CONDUCTIVE MATERIAL ARRANGED CLOSELY ADJACENT TO AND SUBSTANTIALLY CO-EXTENSIVE WITH SAID SPACED ARRAY OF SAID MAGNETIC CORES, SAID PLATE THEREBY HAVING THE EFFECT OF A DISTRIBUTED CAPACITANCE UPON EACH OF SAID CONDUCTORS WHEREBY EACH OF SAID CONDUCTORS AND SAID PLATE CAN BE REGARDED AS TRANSMISSION LINES WITH DISTRIBUTED COMPONENTS; AND AN IMPEDANCE ELEMENT CONNECTED FROM ONE END OF EACH OF SAID CONDUCTORS TO SAID PLATE, EACH OF SAID IMPEDANCE ELEMENTS BEING EQUAL TO THE CHARACTERISTIC IMPEDANCE OF THE TRANSMISSION LINE FORMED BY THE RESPECTIVE CONDUCTOR AND SAID PLATE. 